Concrete-mixer drum.



T. L. SMITH.

CONCRETE MIXER DRUM.

APPLICATION FILED JAN. 23, 1913.

1,150,896. Patented Aug. 24, 1915.

' T a I A? V I5 I; WW I UNITED STATES PATENT OFFICE.

THOMAS L. SMITH, 0F MILWAUKEE, WISCONSIN, ASSIG-NOR TO THE '1. L. SMITH('10., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

v CONCRETE-MIXER DRUM.

Specification of Letters Patent.

Patented Aug. 24, 1915'.

T 0 all whom it may concern:

Be it known that I, THOMAS L. SMITH, a citizen of the United States,residing at Milwaukee, in the county of Milwaukee and State ofWisconsin, have invented a new the drums for concrete mixers andmore-par-' ticularly to the blade arrangement in drums that are .tiltedto discharge.

The objects of my improvement are to increase the mixing efficiency andthe uni-- formity of the discharged product and incidentally to reducethe waste of material splashing out of-the drum. I attain these objectsby the construction illustrated in the accompanying drawing, in whichFigure 1 shows a central longitudinal section of the drum. 7 Fig. 2shows a transverse section ,of the drum on the line 22.of'Fi'g.

1 looking toward theleft, and Fig. 3 shows diagrammatically thearrangement of one set of blades.

Similar reference numerals refer 'to similariparts throughout theseveral views.

I The drum here shown is of a type Well known in the art of concretemixing. The feed and discharge openings are at the "respective ends ofthe drum, concentric with its axis. mixing machine that it is maintainedvin horizontal position during the feeding of the batch to the drum andduring the mixing of the batch, and is tilted to an inclined positionduring the discharge of the batch, the rotation of the drum beingconstant and uninterrupted during the successive performances of thesevarious operations.

-The mixing of the ingredients of which the concrete is composed, sand,stone, water and Portland cement, is effected by the blades attached tothe interior surfaces of the drum.

.10 is the feed opening through which the batch is introduced to thedrum, and 11 is the discharge opening through which the I concretemakesits'exit whenthe axis of the drum is in inclinedposltion.

A series of -bl'adesiI2;:{1s*placed, in the re ceiving end ofutheidruxmand acorrespond ing series ofbla'des' 'flg{isfplacedinthe dis"- chargeend.--These--bl'adesg12 and 13 are The drum is so mounted in the.

in Figs. 1 and 3, and are all inclined rela tive to the drums axis asshown in Figs. 1

and 2. Each pair of blades converges toward the medial cross plane ofthe drum, the. blades of each pair being spaced apart leavmg acomparatively narrow opening 14 betweenthem. The ends of the,bladesforming thls opening being parallel to each other and substantiallyperpendicular to the axis of the drum. The blades are substantiallytriangular in shape, varying in width radially of the drum from the deepedge formlng the opening 14 to nothing as the feed and dischargeopenings --'are approached' The drum is to be rotated in the directionof the arrows 15 of Figs. 2- and 3, that is, with the points of theblades which are near the ends of the drum in advance and the opening 14following in, the direction'of rotation. The blades therefore tendconstantly to force the material contained in the drum, toward themedian'plane thereof and away from the ends thus preventing the waste ofmaterial due to splashing through the open ends of the drum. Also, aseach pair of blades progresses upward on the as- 'cending side of thedrums the material is 1 of the drum auxiliary blades 16 are attached,extending across the openings 14 near the interior surface of the drum.

These auxiliary'blades'also are triangular in shape having their broadsides attached-to the blades 12 and their points directedtowardthedischarge end of the drum. They are also placed at an angle'relat'ivetothe drums axis in such. manner as to tend to throw. the material towardthe discharge end Their function is two fold. First to ,eifectaturningover and anendwise moveiiient of heavy portions of the materialthat might otherwise continually roll around at the la'rgest diameter ofthe drum and placedopposite each other'in pairs'a'sshownthrough theopenings 14 without being which kind. of concrete 1s particularly(sticky and apt to form balls of the size of the openings 14. In suchcase these. balls will be disintegrated by the blades 16 and theircontents thrown into the path of blades 13. The second function of theseauxiliary blades is to equalize the kinds of material in the dischargewhen the concrete which is being produced is off the kind known assloppy concrete which contains an abundance of water. In mixing thiskind of concrete without the'blades 16, the larger and heavier stonesare apt to gather at the bottom of the drum and will be retarded indischarge when the drum is tilted, the more fluid part of the mixtureflowing out first carrying most of the stone with it, but still leavingquite a residue of the largest pieces of stone to form the last of thedischarge. These auxiliary blades .16 not only prevent the stoneaccumulating in the bottom of the drum, but also, by their.

inclination, start what stone happens to be there toward the dischargeopening on the first movement of discharge. The eflt'ect is that thestone in sloppy concrete passes out in its proper proportion to theother ele ments and there isno more stone in the last part of thedischarge than in the first. This movement toward the discharge end ofthe drum is also facilitated by the blades 13 on the discharge side ofthe drum being a little shorter than the blades 12 on the feed sideas-shown in'Fig. 3.- The portion of the blades 12- which extends beyondthe blades 13 will assist iii 'this impulse toward -,the dischargeopening.

- The various details of construction and arrangement .here shown asanexemplification of this invention may be changed without departingfrom the spirit or scope thereof as defined by the claims.

What I claim as my invention, is y 1 A rotary drum for mixing concretecomposed of two frustums of cones attached together at the largerdiameters and having 7 axial feed and discharge openings at theirsmaller diameters; a plurality of pairs of blades attached to theinterior of the drum,

one blade of each pair being attached to each cone opposite to the othermember of the pair, the blades of each pair lying in planes which areequally and oppositely inclined to each other and to the axis of thedrhm similar to the letter V, the adjacent edges of each pair ofopposing blades being spaced apart at the medial plane of the drum, theopposed edges of the blades at the opening between them beingsubstantially radial of the drum, and auxiliary blades of comparativelysmall width radially of the drum attached to said radial edgesof theblades on the feed side of the .drum and extending across theintervening space between the opposed blades, said auxiliary bladesbeing also inclined to the axis of the drum in the same direction as theblades on the feed side of the drum.

2. A rotary drum for mixing concrete composed of two frustums of conesattached together at the larger diameters and having axial feed anddischarge openings at their smaller diameters; a plurality of pairs ofblades attached to the interior of the drum,

one blade of each pair being attached to each cone opposite to the othermember of the pair, the blades of each pair lying in planes rhich areequally and oppositely inclinef ,to each other and to the axis of thedrum similar to the letter -V; the adjacent edges of each pair ofopposing blades being spaced apart at the medial plane of the drum, theopposed edges of the blades at the opening between them being radial ofthe dr im, said'edge on the blades on the the opposed edge of the bladeson the discharge side of the drum as referred to the direction ofrotation of the drum, and auxiliary blades attached to said radial edgesof the blades on the feed side and extending across the interveningopening between the feed side of the drum being slightly behind opposededges, said auxiliary blades being a 0 materially less height radiallyof the drum than the main blades and inclined to the axis of the drum inthe same direction as the blades on' the feed side thereof; all of theblades being substantially tri-angular inform; r

- THOMAS L. SMITH.

Witnesses:

' CHARLES F. SMITH,

E. O. MANKTELOW.

